Click here to go to the NEW College Discussion Forum

based on the following general reaction, if 1.0 mole of A is allowed to react with 2.0 moles of B, which reactant is the limiting reactant and what amount of A2B3 can be produced?

2A + 3B --> A2B3 (the numbers in the products are subscripts)

...this is what i have so far...correct me if i'm wrong:

take 1 mol of A, multiply it by the mole:mole ratio for B and A: 1 mol A x 3 mol B / 2 mol A = 1.5 mol B - which is the required amount and is also the limiting reagent because it only gives us 1 mole of A and 1.5 of B, so B is limited....?

thanks in advance ;)

By Gmikeg (Gmikeg) on Sunday, December 14, 2003 - 02:56 pm: Edit

the limiting agent is A... A2B3 means A combines with B in a 2/3 ratio... since you only have 1 mole of A and 2 moles of B than you have a 1/2 mole ratio... since 1/2 is smaller than 2/3 than you dont have enough A compared to B... the limiting factor is the element that doesn't allow for anymore product to be made
have some1 double check me but i think i remeber a little bit of chem

By Apathetique_0ne (Apathetique_0ne) on Sunday, December 14, 2003 - 04:42 pm: Edit

hey, thanks...yea i think A is the limiting reagent because the reaction requires 1.5 mol of B and it has 2 mols so there's .5 mol left over...eh is this an acceptable reason?? blahhh. i want to take a cathode ray and beam it at my chem book.

By Doofus (Doofus) on Sunday, December 14, 2003 - 09:48 pm: Edit

I think its 3/4 mol.

The limiting reagent is B. For every mol of A you would need 2 mols of B. In this reaction you need 4 mols of B for the 2 mols of A. Only 1.5 mol A can react with 3 B. So 1.5/2=75% yield. 75% of 1 mole is .75.

By The_Chief (The_Chief) on Sunday, December 14, 2003 - 10:28 pm: Edit

Yes, the limiting reagent is A. Think of it as having stamps and envelopes. If you have 5 envelopes and only three stamps, you can only mail three letters. Therefore the number of stamps is the limiting reagent. The other two envelopes left over are called ecxess reagents.

So in your problem, A is the # of stamps and B is the # of envelopes. The one mole of B left over is an excess reagent.